Only a quarter of the British public plan to vote "yes" in the planned referendum on the European constitution, a new poll has suggested.

The ICM poll found just 25 per cent of those surveyed said "yes" when asked: "Do you believe Britain should sign up to the EU's constitution?"

Some 55pc said "no", with just 20pc undecided.

But the poll also revealed that the British public believe strongly that Britain must not withdraw from Europe altogether. Almost two thirds of those expressing an opinion said they believed that Britain should stay in the EU.

The poll, conducted for a London- based Sunday newspaper, also suggested that Mr Blair's abrupt U-turn over a referendum did little to enhance his personal standing with voters.

Just 10pc said his reputation had improved since he announced last week that there would be a public vote, with 35pc saying it had gone down.

ICM Research interviewed 1010 adults aged 18-plus across the country by telephone on April 22 to 24.